Interposer assemblies typically include plastic plates with through passages and contacts in the passages for forming electrical connections between opposed contact pads.
Interposer assemblies form electrical connections between contact pads arranged in a very close proximity to each other. The pads may be arranged on a one millimeter center-to-center grid. Each assembly may include as many as 961 contacts with four interposer assemblies mounted in a single frame with a total of 3,844 contacts in the frame. The contacts must establish reliable electrical connections with the pads when the assemblies are sandwiched together between circuit members. Failure of a single contact to make a reliable connection renders the entire frame useless.
Contacts in interposer assemblies include contact surfaces which mechanically engage the contact pads and form electrical connections with the contact pads. Conventional interposer assemblies have single surface contacts which engage each pad to form a single electrical connection with each pad. The contact may wipe along the pad to improve the quality of the electrical connection. Impurities, oxides or contaminants on either the contact surface or the pad can impair the single surface electrical connections with the pads. Contacts used in interposer assemblies are typically symmetrical about the center of the insulating plate, each including a separate spring which biases a single contact surface against a pad.
Accordingly, there is a need for an improved interposer assembly in which each contact makes redundant contacts with each pad so that when the assembly is sandwiched between overlying and underlying substrates each contact establishes two reliable electrical connections with each pad. The connections should have small contact areas to increase the contact pressure between the contact and the pad. Wiped high contact pressure redundant connections would provide reliable interposer assembly electrical connections. There is also a need for a method of making a contact with spaced contact points from strip stock, which may be very thin and difficult to form.
Further, there is need for a spring contact having spaced contact points for engaging a contact pad and forming redundant wiped high pressure redundant electrical connections between the contact and the pad.